High Gear WOT???

[Boomba Racing]

Here's everything you'd want to know and more about LSPI:

http://stratifiedauto.com/blog/low-speed-pre-ignition-in-the-mazdaspeed-disi-and-ford-ecoboost-motors/

 

[JasonHaven]

Here's your general warning: Just don't.

I got that loud and clear, I was just saying that as a general idiot, I appreciate this thread, and the info contained within it, and the questions (at least on my part) are just for more education.

 

[JasonHaven]

Here's everything you'd want to know and more about LSPI:

http://stratifiedauto.com/blog/low-speed-pre-ignition-in-the-mazdaspeed-disi-and-ford-ecoboost-motors/

This is good, thanks!

 

[GAbOS]

Agreed. Thanks, Boomba!

I don't WOT to pass at 80mph, but close. I feel better about that now as I am confident the RPM I am running in these situations is enough to keep this from happening.

..and for everyone else..
I'm not sorry for requiring more information than "just don't" concerning issues that may "blow up my motor".

 

[Kip2MyLou]

And this is why I made the thread. Sharing is caring!

 

[Maxpowa]

Great info. for someone like me (new to the DI turbo scene.) I don't WOT in 6th but do catch myself rolling into the throttle in lower gears at low RPMs. I'll rethink my driving habits and pay less attention to the up-shift arrow as well. I run high-octane (no tune), so hopefully all is still well with the engine at 6700 miles.

 

[Vince62]

Always down shift when passing.It's all in the fun of this car.

 

[OrangeFiST]

Very valuable info indeed. All technical stuff aside, it does seem pretty obvious to me that if the engine lugs, its time to downshift; otherwise it feels like I'm pouring more gas into the cylinders than is optimal.

 

[Goingnowherefast]

Wow well I just want to say thanks to the OP. I didn't end up buying the Fiesta ST, but hopefully you guys can get this figured out and minimized.

Here's everything you'd want to know and more about LSPI:

http://stratifiedauto.com/blog/low-speed-pre-ignition-in-the-mazdaspeed-disi-and-ford-ecoboost-motors/

This is a great link man.

 

[IrishST]

Sorry to necro this, but I've been reading up on this and have done a lot of forum searching without definitive answers to my specific questions, including in this thread. I found some more "detailed" information as it pertains to the Focus ST, but that isn't the Fiesta ST and has a totally different engine so I don't want to blind follow that stuff.

Regarding LSPI and damage to the engine, I get the concept completely and I don't regularly go around flooring it in 6th when cruising at 50-60mph with low-ish RPM, but because our engines are so small I'm left with a few very specific questions:

1. I honestly haven't done a lot of highway driving since getting the car, but I feel like when I'm cruising at 75 in 6th I'm sitting at 3k-3.2kish RPM. Is that still considered too low to go WOT? The Focus information I found said you shouldn't really go WOT in 5th OR 6th unless you're at 3.5k RPM or more. I prefer to downshift for the go juice, but sometimes downshifting isn't practical or you're not trying to blow away the car you're passing.

2. What about 1st and 2nd gear? We are boost limited from the factory in 1st and 2nd and while part of that is to help with traction, I was always under the impression the other part was helping prevent LSPI while allowing you to launch decently. The MP215 kit which is Ford and warranty approved maintains the limitations in first, just raising them slightly, as well so it seems like Ford considers this important. Are you safe to go WOT in 1st from a standstill? What about 2nd?

3. Any special considerations for mid-gears, 3rd and 4th?

Again, I'm sorry to bump an old thread, especially one that some seem to have already felt was an unnecessary retread, but I can't seem to find answers to these specific questions, at least not direct answers. I grew up with N/A motors and I'm new to turbos, especially low displacement DI turbos, so I really don't want to jack up my car while trying to have fun.

 

[Hijinx]

Sorry to necro this, but I've been reading up on this and have done a lot of forum searching without definitive answers to my specific questions, including in this thread. I found some more "detailed" information as it pertains to the Focus ST, but that isn't the Fiesta ST and has a totally different engine so I don't want to blind follow that stuff.

Regarding LSPI and damage to the engine, I get the concept completely and I don't regularly go around flooring it in 6th when cruising at 50-60mph with low-ish RPM, but because our engines are so small I'm left with a few very specific questions:

1. I honestly haven't done a lot of highway driving since getting the car, but I feel like when I'm cruising at 75 in 6th I'm sitting at 3k-3.2kish RPM. Is that still considered too low to go WOT? The Focus information I found said you shouldn't really go WOT in 5th OR 6th unless you're at 3.5k RPM or more. I prefer to downshift for the go juice, but sometimes downshifting isn't practical or you're not trying to blow away the car you're passing.

2. What about 1st and 2nd gear? We are boost limited from the factory in 1st and 2nd and while part of that is to help with traction, I was always under the impression the other part was helping prevent LSPI while allowing you to launch decently. The MP215 kit which is Ford and warranty approved maintains the limitations in first, just raising them slightly, as well so it seems like Ford considers this important. Are you safe to go WOT in 1st from a standstill? What about 2nd?

3. Any special considerations for mid-gears, 3rd and 4th?

Again, I'm sorry to bump an old thread, especially one that some seem to have already felt was an unnecessary retread, but I can't seem to find answers to these specific questions, at least not direct answers. I grew up with N/A motors and I'm new to turbos, especially low displacement DI turbos, so I really don't want to jack up my car while trying to have fun.

Probably because there are no specific answers to your specific questions. Just try to refrain from WOT in 6th gear... Because I doubt you'll ever have enough road to actually need to be in WOT at 6th. It's an overdrive gear. And hey, if you wanna drop the hammer at WOT in launch control go for it...it's not very effective, though. 3rd and 4th are gonna depend on your tuner... I do both 3rd and 4th gear logs starting at 2krpm. That doesn't mean your tuner will want that from your specific car... Like I said, I don't think there are any specific answers to your specific questions because there are lot of variables.

 

[dyn085]

I run third and fourth from 1500 rpm. First and second, zero effs are given. Fifth and sixth don't get anything over 5 psi, let alone full-boost.

 

[twolf]

I'm under the impression that as long as your knock sensors aren't picking up knock and you're not getting negative corrections, you're fine? Or is it possible to have LSPI with no knock shown by the sensors?

 

[dyn085]

I'm under the impression that as long as your knock sensors aren't picking up knock and you're not getting negative corrections, you're fine? Or is it possible to have LSPI with no knock shown by the sensors?

The problem with LSPI is that it happens so fast that by the time you realize there's knock it's over. At just 2k rpm your engine has turned over 33 times, which is greater than 16 cycles. Realistically speaking, we just can't react fast enough to negate it.

I really haven't seen any trend towards it in the FiST community. Not yet, at least.

 

[IrishST]

I should note that I'm not tuned yet. I'm going with the MP215 kit in the very near future once they officially release the "2016 approved" version so I won't be doing a lot of logging runs and working with a tuner to tweak my settings because there isn't anything to tweak . I'm just curious from a general standpoint of what's really bad and going to blow shit up, what's not so bad, and what's safe.

I don't often find a need to go flooring it in 5th and/or 6th, but I guess my confusion stems from the general explanation of "high boost under load at low RPM". It is the easiest to have this happen in 6th gear as it is a cruising gear, but on the flip side, cruising along at 75-80 in 6th kind of takes you out of "low RPM" so I just wasn't sure if that was still considered really bad, or just kinda bad, or what. Obviously when you're using 6th for gas mileage savings at 45mph you wouldn't want to do this, but that isn't quite the same as being on the highway cruising at 3k+ rpm in 6th.

That's good to know about 1st-4th though. I totally understand that outright flooring it from a stop in 1st isn't going to get you much because of traction, I was just asking from a theoretical perspective - "could you do it without frying a piston or buckling a rod". If I'm getting on it, no gear save 1st is going to be lower than 1500rpm (and in 1st I'm going to feather/roll until I have more traction anyway) and I'm not going to pull beyond 4th because I'm not trying to go to prison, so I should be just fine in this sense.

I just wanted to make sure that when I'm rolling along at 35 in 3rd gear and the speed limit changes up to 55 so I womp on it for grins from ~2-2.5k rpm I'm not going to break things. Conversely, if I want to get on it from a stop and I get a little too heavy I'm also not going to break things. Granted, breakage happens all the time for unknown reasons, I'm just trying to not add things to the mix that can increase the chance.

Thanks for taking the time to reply, I appreciate it.

 

[dyn085]

The way I would look at it would be to compare it to an automatic. Unless you're going seriously fast in a six-speed automatic, it's always going to shift down at least one gear if you go WOT. Our powertrains are no different, we just have to control the shift.

I should also clarify the fact that the reason I have no issue with going WOT in third/fourth at 1500 rpm is because I do my own tuning. 2k is probably a more reasonable recommendation.

The issue of going WOT in higher gears, aside from LSPI, comes with metal fatigue. Our rods may hold a sixth-gear WOT run from 3k without issue, but due to the extended period of time that it takes to accelerate, the amount of load placed on them is significantly higher because of the slower rotation. Not the instantaneous load, the amount of load distributed to them over the course of the entire acceleration. Eventually, at some unknown point in time, they will have fatigued enough to not be able to withstand that higher load for an extended interval.

Tl;dr-Don't necessarily think of WOT in sixth as instantaneous death, think of it as taking miles off the top-end of overall longevity.

 

[IrishST]

Makes perfect sense, thanks again!

 

[GAbOS]

The way I would look at it would be to compare it to an automatic. Unless you're going seriously fast in a six-speed automatic, it's always going to shift down at least one gear if you go WOT. Our powertrains are no different, we just have to control the shift.

I should also clarify the fact that the reason I have no issue with going WOT in third/fourth at 1500 rpm is because I do my own tuning. 2k is probably a more reasonable recommendation.

The issue of going WOT in higher gears, aside from LSPI, comes with metal fatigue. Our rods may hold a sixth-gear WOT run from 3k without issue, but due to the extended period of time that it takes to accelerate, the amount of load placed on them is significantly higher because of the slower rotation. Not the instantaneous load, the amount of load distributed to them over the course of the entire acceleration. Eventually, at some unknown point in time, they will have fatigued enough to not be able to withstand that higher load for an extended interval.

Tl;dr-Don't necessarily think of WOT in sixth as instantaneous death, think of it as taking miles off the top-end of overall longevity.

This I agree with and thank you for using "Time on load".

I got flamed hard for saying that I had no issue passing people in 6th at 3k.

 

[RAAMaudio]

The way I would look at it would be to compare it to an automatic. Unless you're going seriously fast in a six-speed automatic, it's always going to shift down at least one gear if you go WOT. Our powertrains are no different, we just have to control the shift.

I should also clarify the fact that the reason I have no issue with going WOT in third/fourth at 1500 rpm is because I do my own tuning. 2k is probably a more reasonable recommendation.

The issue of going WOT in higher gears, aside from LSPI, comes with metal fatigue. Our rods may hold a sixth-gear WOT run from 3k without issue, but due to the extended period of time that it takes to accelerate, the amount of load placed on them is significantly higher because of the slower rotation. Not the instantaneous load, the amount of load distributed to them over the course of the entire acceleration. Eventually, at some unknown point in time, they will have fatigued enough to not be able to withstand that higher load for an extended interval.

Tl;dr-Don't necessarily think of WOT in sixth as instantaneous death, think of it as taking miles off the top-end of overall longevity.

Very well put, thanks for taking the time to do this

Rick

 

[milkman42]

Good discussion guys, thanks. As a turbo noobie this wasn't intuitive to me either.